<!DOCTYPE html>
<html>
<head>
    <title>Dynamic style</title>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <script type="text/javascript" src="../test.js"></script>
    <style id="style">
        @font-face {
            font-family: 'Roboto';
            font-style: normal;
            font-weight: 400;
            src: local('Roboto'), local('Roboto-Regular'), url(https://fonts.gstatic.com/s/roboto/v18/CWB0XYA8bzo0kSThX0UTuA.woff2) format('woff2');
            unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2212, U+2215;
        }
        body { font-family: "Roboto", serif }

        div {
            padding: 20px;
        }
        .div1 {
            background: darkred;
            color: white;
        }
        @media (min-width: 10px) {
            .div1 {
                background: darkgreen;
            }
        }
    </style>
    <script>
        document.querySelector('#style').sheet.insertRule(
            '.div2 { background: darkgreen; color:white; }',
            document.querySelector('#style').sheet.cssRules.length
        );
    </script>
</head>
<body>
<div class="div1">Static styles</div>
<div class="div2">Dynamic styles</div>
</body>
</html>

